Engine/Transmission (1994 - 1998) Compound / Twin Turbo Suggestions?

[MMcCallie]

My Excursion has a tight fit for my '94 Cummins. The stock manifold sets the turbo against the a/c components. I've purchased an '06 manifold to move the turbo further back and down, hugging the engine block closer to my frame.



I've been told my turbo has a bit of play and will need to be replaced soon. Since no intake or exhaust plumbing has begun yet, this is my best opportunity to set up compound turbos.



The engine is currently bone stock. I plan on modifying the cam plate for more fuel, and eventually throwing in some big injectors. This truck weighs about 9,000lbs empty and does tow from time to time. When towing, it is rarely less than 1,000 miles at a time so it needs to have no surging or EGT problems. I live in Colorado so i need to have flexibility for altitudes.



I have an immediate power goal of 300 hp and eventual of 500 hp to the ground. I am also hoping to get over 20 mpg. I would like it to burn as clean as possible, no smoke. Most of my driving is extreme stop and go under 35 mph. I'd like this truck to really launch and easily break traction on demand.



I need to keep my cost as low as possible. Should i send my stock turbo off to be modified for faster spool up? Would i be better off buying a used turbo off a newer engine that uses a smaller housing? How low an RPM can a turbo light? What should i use for a big turbo underneath? How big do i need to be to support 500 hp with no EGT concerns? Is it possible to never see 1,500 degrees? Will the difference between big and small turbos cause any possible gap in the midrange?



I'd also like to have at least a 4" downpipe. Is a 5" exhaust worth the extra inch over a 4" in EGT reduction? As much as i'm trying to stay low budget, i'd like to do this once and get it right. Is there a single turbo that can meet all of my demands and save me money?



Thanks in advance,

Matt

 

[OPoole]

I have a stock exhaust manifold off a 05 if you need it.

 

[MMcCallie]

Thank You OPoole,

I just purchased an '06 manifold on eBay this afternoon. It has been used for 6,000 miles and is supposed to be in good shape. I think i'll need new bolts and gaskets though. Do people use studs on a stock manifold or do they hold alright?

Thanks,

Matt

 

[wildmanben]

get a Super Stock 62 from HTT. spools like stock and can still get you past 500hp.

 

[MMcCallie]

High Tech Turbo has talked me out of using twins. Seems that many customers were unhappy, endlessly tuning, and are returning to a single turbo setup. I called a bunch of different companies today and it is amazing how different everyone's opinion is on how much power certain mods will make, and what route to go.



I was told most turbos last no longer than 120,000 miles. I was also told that a stock HX35 can last well over 400,000 miles if it hasn't had too much fuel for too long. I've been told the stock turbo doesn't spool until over 2,000 RPMs. I've also been told the stock turbo will spool almost immediately.



Some have told me a cam plate on a 160 pump will make over 300 hp, some have said not even 250 hp. Some say 3k springs add more power because of the increased RPMs. Some say they decreased power output because it takes too much effort to spin that fast.



One of the reasons i swapped to a Cummins from the Powerstroke was more power for less money. To spend $3,000 on a pump, then another grand on injectors, and $1,500 on a turbo isn't as cheap as i'd hoped. I think i need to research cheap mods that don't require buying expensive parts and still make solid, reliable gains. Suggestions?

 

[Buck88]

#10 Plate, 3k GSK, High Flow Dilivery Valves, Marine 370's, SPS 62 by industrial injection



10 Plate - Got my 6 used for $100

3k GSK - $125 Piers

HF DV's - $250 ish

Marine 370's - Used $200

II SPS 62 - $1400 ish



Good start I would say. Though I don't tow, so I don't know how hot you would get with this setup.

 

[Buck88]

woops... missed the part about not wanting to smoke too hard.

 

[CSchafer]

my dad's 94 has the 160 pump. It has a 5 plate, 3k's, 15* timing and is great. Not super fast but smooth reliable towable power. It has had this setup for over 200,000 miles with 350,000 on the clock. I just resently put some edm'd 370's in it for him and wow. It runs great but would probobly need some more air if he were going to tow. I have the htt 62/12 on my first gen and I love it, I wouldnt say it spools quite like stock but close and it cools awsome. If you can fab up your own twins and keep the hx 35 that would be your cheapest route but for simplicity of bolt on and great performance I would go with a single.

 

[BIG C]

Id be curious to see how close your turbo sits to the HVAC unit? Is it even poosible to get the stock turbo on there with the stock manifold? Got any pics? Mine turbo was very tight to the HVAC unit and the bottom turbo fit pretty decent underneath but the piping is TIGHT! With the new turbos coming out I might try a single. With the extra turbo the EGT's are no longer a concern unless its extreme conditons.



Id like to hear about your conversion. Its been 2. 5 since I did mine, about 8 months with the twins, and I absolutely love it.



Good Luck!

 

[MGarland]

Matt, look at my sig, my truck is a solid 300 rwhp and I tow a 32' enclosed gooseneck trailer everyday. I can control the heatwith my right foot and still run 75 mph down the interstate. I really like the setup but I wish that I would have bought the 62/14 instead of the 62/12. Just my . 02.

Mark

 

[BLujan]

Matt, if it's not too late that 06 manifold won't work on a 12v. They do make a 12v manifold in that same style, it was on the big ford trucks in the mid 90's I think it might be a F-850.

 

[BIG C]

Matt, if it's not too late that 06 manifold won't work on a 12v. They do make a 12v manifold in that same style, it was on the big ford trucks in the mid 90's I think it might be a F-850.

Thats kind of what I was thinking. The ports dont make. There are at least 2 different manifolds for the 12 valve that put the turbo down towards the block. One of them puts the turbo right in the middle of the manifold and the other moves it back further toward the firewall. I looked into both but got the regular stock manifold to work. Depending on who did your swap and where they placed the engine, you might be able to get your stock manifold to work. Have you tried it yet?



Chad

 

[MMcCallie]

Thanks for all the input,



The manifold won't show until mid next week. I've called a bunch of people about swapping manifolds and everyone thinks it will work. In fact, i know a guy who has a 12 valve manifold on a 2003 24 valve engine. He also has compound turbos in his Super Duty.



The 24 valve manifold has rounded ports, the 12 valve manifold uses squared corners. The ports will supposedly line up so air will flow, just not a perfect match. I've been advised to use an '06 gasket and that it should work fine, no problems.



I'm trying to avoid having to use injectors for now. Again, i get different advise on the subject for high altitude driving. Most say it will be easy to over fuel so go no bigger than stage 3s. Others tell me with the right tuning, i would get better fuel economy with stage 4s. Any opinions based on experience?



After the '06 manifold, i'm gonna start out stock. I expect it to be puny in this heavy truck, geared as it is. I'll slide and grind the plate for a free upgrade and raise the timing to about 15. 5 for now. Unless someone would trade me power upgrades for my PSD, i can't afford mods.



This project has already tripled beyond expected cost. Must say the destroked.com kit went together perfectly. The autoworldmt.com quad engine mounts have put the turbo against the HVAC. Twins really are too expensive. I think i would rather wait to upgrade into a built 215 pump, stage 4 injectors, and a 62/12 or 14 turbo. I would probably be around my 500 hp goal.



I just heard about a guy with a 12 valve who can blip the throttle at 40 mph and spin the tires. Dyno of around 550 hp. Gets 28 mpg. That's how i'd like to have my truck perform. I figured the Cummins is the only engine capable of such possibilities. PSD was getting 11 mpg and could only spin a tire on very wet pavement from a stop. That was with chips and other mods like water/methanol injection.

 

[Bandit1]

with a built 215 pump your egts will be high, i know mine are with my 180 pump. you have got to have airflow to match the fuel, it is all about tuning and ratios to make good clean power. just a brain fart but you couldnt turn your ex manifold upside down like you were doing twins and get your charger past the other components could you.

 

[MMcCallie]

Good Suggestion,



A couple of the bolts in my exhaust manifold were backed out and bent. The stock manifold seems to have shrunken. The gaskets look a little funky too. Moving it up high would be possible, but difficult.



I have a huge 32 lb Mitsubishi alternator that puts our about 300 amps. I'm having to turn it upside down and mount it with an adapter from autoworld that makes it stick out even further. It is internally regulated, won't have to mess with the Dodge PCM or alternator. Mounting it high would also make it even tighter to route an intake.



I think i'm already going to have to move both batteries to the driver's side to make room for an air cleaner, unless i come up with a way to make use of the engine driven vacuum pump to replace the electric pump on the passenger side fender. Also, i will likely have to rig up a remote oil filter because the stock one may become impossible to access. More room than with the PSD, but converting requires some new feng shui. Once the new manifold arrives, piping and space requirements will become more clear.

 

[JKouzez]

if i remember correctly on my 160 pump with a 6 plate 3k gsk 370s afe 16 timing strainght pipe exhaust and a worn out stock transmission i put down 324HP 790 TQ. it was a great combo smoke and egts were very easily contrlolled. now with my current set up egts are about 1300 max run mid 13s down the quarter and have yet to break 450HP on the dyno. my homemade twins set up only cost me a few hundred bux more than the top of the line singles. granted alot of the new singles have com a long long way,by he way this is of course all at sea level. Just outta curiosity what kinda transmission are you putting behind it. I know the stock dodge transmission wont hold 300+ reliably not sure about the fords and i dont think any stock transmission will hold 500+.



P. S. sounds like an awesome project.

 

[MMcCallie]

I'm new to high altitude, been in Boston a few years, i run out of breath quickly here in Colorado. I have yet to feel the effects of altitude on a diesel. 300 hp has been my immediate goal since i had my truck on a dyno this summer. My PSD made 271 hp tops so i feel i have a good idea of what i'd be temporarily satisfied with.



I don't want to spend money twice on anything. If it ain't broke don't fix it... but fix it right, fix it once. Hard to talk myself into turbos and injectors i know i'll outgrow. I have my doubts that the 160 pump will support my truck's future in the long run.



The transmission is a BTS 4R100. Supposed to be about the toughest light truck transmission you can buy. Much bigger and stronger than a Chrysler transmission. Brian explained the reasons that the 4R100 is a better design, but i couldn't recite any of it now.



I got to watch him build it. He gutted the old one and put bigger, stronger parts in a brand new housing for me since i'd cracked my old case. It ought to handle absolutely any amount of power this truck will ever feed it. The flexplate is SFI to a good 1,000 hp. Basically, i'm making this truck as tough as i know how/can afford. It should take me to the remote locations in the mountains i want to see and last many rewarding years. That's the plan.

 

[BIG C]

Let us know on the manifold and how it works. I would think you could put a 12V manifold on a 24V but not an '06 on a 12 valve. I could be wrong. Curious to know. I used a stock 12V manifold on mine and fliped it upside down to raise the top turbo a little. The top turbo sits right against the HVAC system but it works. Good luck with your project.



I have to say I hear a lot of BS on the net and just blipping the throttle at 40mph will not spin the tires. Sure its possible to spin em at 40 MPH but a "blip" will not do it. These motors arent like gassers and the chargers need some fuel to spin.



Good Luck!



Chad

 

[MMcCallie]

Well, while i was away, the mechanic who took over the project didn't even look at the truck for weeks. He's the one who told me i had to get a different manifold. After the new one arrived he tried it and realized the stock 12 valve manifold was fine. I don't know what he was thinking, ran into that sort of thing many times.

Now that i have enough fuel, i'm leaning toward a set of compounds again using my HX/35 and most likely an HT3B. Or is an S400 (B2) that much better? Only if i can do it all for under a grand and without weeks of waiting and tracking down parts.

 

[Bandit1]

the 35 is going to restrict the entire setup